Photographic shutter



Nov. 17, 1942.

E. STRASSENB URG PHOTOGRAPHIG SHUTTER Filed Jan. 19, 1940 2 Sheets-Sheet1 -,e i l q: K1730 80 a p Nov. 17, 19 E. STRASSENBURG ,3

PHOTOGRAPHIC SHUTTER Filed Jan. 19, 1940 2 Sheets-Sheet 2 "WVEIG'TOR. m!c LsmAssm/B U126 ATTORNEY.

Patented Nov. 17, 1942 PATENT OFFICE PHOTOGRAPHIC SHUTTER EricStrassenburg, New York, N. Y., assignor to Histra Corporation, New York,N. Y.

Application January 19, 1940, Serial No. 314,578

12 Claims.

My invention relates to photography, and more particularly tophotographic shutters.

One object of my invention is to provide a shutter of simpleconstruction having only three main elements in the actuating mechanism.

Anotherobject. of my invention is to provide a shutter in which theactuating mechanism has only two pivots and these pivots may be used forthe swingable mounting of the shutter blades and for the connection ofthe mounting plate with the casing.

A further object 01' my invention is to provide a simple two-bladeshutter with a bulb exposure and an instantaneous exposure.

In order to carry out my invention, I provide a photographic shuttercomprising shutter blades, a pivoted blade carrier for operating saidshutter blades, a first spring connected to said blade carrier forreturning same into its normal position to hold the shutter blades inclosing position, a pivoted trigger, a second spring connected to saidtrigger for returning same into its normal inactive position, a springpressed actuator, said actuator being movably connected with saidtrigger and being disengaged from said blade carrier when the trigger isin its normal inactive position, said actuator being adapted to bebrought into engagement with said blade carrier, stationary means in thepath of said actuator for causing a relative movement between thetrigger and the actuator to tension the spring of said actuator duringthe movement of the trigger into active position, and means forreleasing the spring pressed actuator for an engagement with the bladecarrier so as to actuate same.

The above mentioned objects and advantages as well as other objects andadvantages will be more fully disclosed in the following specificationreference being had to the accompanying drawings forming part of thisspecification, in which:

Fig. 1 is a rear end view of the shutter, the shutter blades and thecasing usually closing the shutter being partly removed to show theparts of the shutter mechanism in normal inactive posiwhich the triggeris in its active end position and 55 the blade carrier is held in theposition for open shutter blades,

which the trigger is in an intermediate returning position and theactuating lever is in a position to become disengaged from the bladecarrier,

Fig. 5 is a fragmentary rear end view of the position. and the actuatinglever is in a position to become disengaged from the blade carrier,

15 Fig. 6 is a fragmentary rear end view of the shutter adjusted forinstantaneous" exposure, the parts of the shutter mechanism being in aposition in which the trigger is in its active end position and theblade carrier disengaged from the 20 actuating lever is in its normalposition to hold the shutter blades in closing position,

Fig. 7 is a somewhat diagrammatical sectional view, taken on line 'I'|of Fig. 2, illustrating the position of the actuating lever and theblade carby the actuating lever,

Figs. 8 and 9 are dlagrammatical illustrations similar to that shown inFig. 7, in which, however,

the parts of the shutter mechanism are in differcarrier shortly beforetheir disengagement,

to that shown in Fig. 10, in which, however, the

parts of the shutter mechanism are in a different position occupiedduring the instantaneous" exposure,

Fig. 12 is a perspective view of the trigger with the spring pressedactuating lever hinged thereto,

Fig. 13 is a fragmentary side end view of the trigger with the actuatinglever in section,

Fig. 14 is a perspective view of the blade carrier,

Fig. 15 is partly a side end view and partly z cross-sectional view ofthe shutter taken on lint l5--l5 of Fig. 1, some parts of the shutterbeing omitted for the sake of clarification,

Fig. 16 is a plan view of a shutter blade in enlarged scale,

I Fig. 17 is a plan view of the shutter blades-in closing position,

Figs. 18 and 19 are plan views of the shutter shutter adjusted for"instantaneous exposure, the parts of the shutter mechanism being in aposition in which the trigger is in its active end rier shortly beforethe blade carrier is actuated Fig. 11 is a diagrammatical illustrationsimilar blades in various intermediate opening positions, and

Fig. 20 is a plan view of the shutter blades in fully opened position.

Referring now to the drawings, 38 indicates a mounting plate Carryingthe mechanism of the shutter. Said mounting plate has a cylindricalcenter portion 32 (Figs. 1 and 15) with a screwthreaded inner surfacefor the reception of the lens mounting. The bottom 34 of the cylindricalportion 32 is provided with the light admitting aperture 36. The casing38 of-the shutter has a screw-threaded collar 48 for engagement with thecamera. Three hollow studs 42, 44 and 48 are rigidly secured to themounting plate 38 in any suitable manner. Said studs have an innerscrewthreaded surface, and the casing 88 is connected to the mountingplate 38 by means of screws 41 screwed into said studs. The mountingplate 38 has a shoulder 48 (see Fig. 15) at its outer surface. A ring 58of the setting mechanism for bulb" and instantaneous exposures isslidably mounted on said shoulder 48. A facing plate 52 screwed to theouter surface of the mounting plate 38 holds the ring 58 in itsposition. A stop pin 54 secured to the ring 58 is in slidable engagementwith a curved slot 58 of the mounting plate 38. A pointer 58 projectingfrom the casing 38 forms a part of a usual iris diaphragm mechanism 88.

A trigger 82 is swingablymounted on the stud or pivot 42. A lever 84 ofthe trigger projects from the casing of the shutter through a slot 88for manual operation of the trigger. A lug 88 of the trigger may serveas an abutment for cooperation with the end of a conventional wirerelease (not shown in. the drawings). A spring I8 stretched between thetrigger 82 and a pin I2 secured to the mounting plate tends to draw thetrigger into its normal inactive position shown in Fig. 1.

An actuating lever I4 is pivotally connected to the trigger 62 by meansof a hook I6 or the like secured to the trigger at an eccentric pointthereof. As best shown in Fig. 12, the length of the shaft of the hookis somewhat larger than the thickness of the actuating lever I4. Thus.the actuating lever I4 may be rotated about the shaft of the hook I4and/or may be moved relatively to the base of the trigger 82 with itspivoted end sliding along the shaft of the hook or tilting about thesame. The trigger 82 has a cam-like surface I8 and an abutment 88cooperating with said actuating lever I4. A cylindrical spiral spring 82is wound around the pivot 42. One end 84 of said spring 82 is engagedwith the body of the trigger, and the other end 88 of said spring isengaged with the actuating lever I4 in such a manner, that the springurges the actuating lever I4 against the cam I8 and against the abutment80. In the normal inoperative position of the trigger 82 shown in Fig. 1the actuating lever I4 is held against the abutment 88 by the spring 82and its main body is at a certain distance from the base of the triggeras shown in solid lines in Fig. 13. The spring 82 urging the actuatinglever I4 against the abutment 88 provides for a joint movement of thetrigger and the actuating lever as long as the actuating lever is notarrested by a post 88 secured to the mounting plate 38. The cooperationbetween the post 88 and the actuating lever I4 will be described inconnection with the description of the operation of the shutter.

A blade driving means or blade carrier 98 is swingably mounted on thestud or pivot 44. One end of a cylindrical spiral spring 82 wound aroundthe pivot 44 abuts against the wall of the center portion 32 of themounting plate 88 and the other end of said spring 82 is engaged withthe blade carrier 88. The spring 82 tends to draw the blade carrier 98against the post." into its normal position to hold the shutter blades84 and 88 in closing position asshown in Fig. 17. The shutter blade 84is swingably mounted on the pivot 44 of the blade carrier 98 and restson the upper arm thereof. The shutter blade 88 is swingably mounted onthe pivot 42 of the trigger. Each of the shutter blades 84 and 86is-provided with a slot 88, and a lug I88 arranged at the upper arm ofthe blade carrier 88 is in engagement with the slot 88 of both shutterblades, so that the shutter blades are interlocked with each other andare moved when the blade carrier is rotated about its pivot. As bestshown in Fig. 14, the lower arm of the blade carrier 88 is provided withan abutment I82 having an inclined upper surface I84. Said abutment I82cooperates with 'the free end of the actuating lever I4 as will bedescribed hereinafter.

The operation of the shutter is as follows:

- Bulb-exposure The setting mechanism is set for bulb"- exposure. Forthis purpose the ring 88 is rotated about the shoulder 48 into aposition, in which the stop 54 contacts the right hand end I88 of theslot 58 as shown in Figs. 1 to 4. Then, the trigger 82 is rotated in thedirection of the arrow A (Fig. 1) about its pivot 42 against the actionof the spring 18. The actuating lever I4 Joins the movement of thetrigger. until it abuts against the post 88 which is in the path of theactuating lever I4. Now, the actuating lever I4 is arrested, and, duringfurther rotation of the trigger 82 in the direction of the arrow A, arelative movement between the trigger and actuating lever occurs, as theactuating lever I4 is rotated about the shaft of the hook I8. Saidrotation of the actuating lever causes a tensioning of its spring 82. Atthe moment of contactbetween the actuating lever I4 and the post 88, theactuating lever is in the elevated position a as shown in Figs. '7 and13. When during the continued rotation of the trigger 82 theactuatinglever I4 is rotated about the shaft of the hook 18 as describedabove, the spring 82. urges the actuating lever downward against the camI8 and thereinafter against the base of the trigger, so that theactuating lever riding on the inclined surface of the cam and movingalong the base of the trigger is brought into the lower position b asshown in Figs. 7 and 13. Furthermore, the eccentric arrangement of thehook I8 on the trigger 82 causes a sliding movement of the end of theactuating lever I4 on the post 88 in the direction of the arrow B (Fig.2). A portion of the post 88 is cut off at I88, and, as soon as the endof the actuating lever is moved past the edge II8, the actuating leveris released and is moved against the abutment I82 of the blade carrier88 by the action of the spring 82 whereby the blade carrier 88 isactuated and is swung into the position shown in Fig. 3, in which theshutter blades are in the open position shown in Fig. 20 and the bladecarrier 88 is arrested by the stop 54 of the setting mechanism adjustedfor bulb-exposure as shown in Fig. 3. The trigger 62 is already in itsactive end Position. in which its abutment 88 rests against the wall ofthe center portion 82. The actuating lever 18, however, which has beenrotated about the pivot 18 during the actuation of the blade carrier 88,is not yet in contact with the abutment 88 of the trigger. The actuatinglever 14 is still in engagement with the arrested blade carrier andlocks the latter in the position for open shutter blades. Moreover, theactuating lever is still in a lower position as indicated by c in Figs.8 and 13, i. e. the actuating lever has not yet been raised by the camI8.

If it is desired to bring the shutter blades into closing position. theactuating lever 18 must be disengaged from the blade carrier 88. Thiseffect is obtained in the following manner. As soon as the user of theshutter releases the trigger 82, the latter is rotated incounterclockwise direction by the spring I8, whereby the cam 18cooperating with the actuating lever 18 lifts the latter into theelevated position d slightly above the highest point of the abutment I82of the blade carrier as shown in Fig. 8. Fig. 4 illustrates the positionof the elements in the shutter mechanism, in which the actuating leveris in said elevated position and is engaged by the abutment 88 of thetrigger. The elevation of the actuating lever I8 causes a disenga ement.of said actuating lever from the blade carrier 88, and the releasedspring 82 of said blade carrier causes an immediate return movement ofthe latter into its'normal position shown in Fig. 1, in which the bladecarrierholds the shutter blades in closing position. On the other hand,the return movement of the trigger 82 by means of its spring I8 into itsnormal inactive position shown in Fig. 1 is continued. The actuatinglever 18 participates in this movement of the trigger by means of theabutment 88 bearing against the actuating lever. Before the returnmovement of the actuating lever will be described, it may be mentionedthat according to Fig. 9 the post 88 has an inclined upper surface H2and that the level of the highest point of the post 88 is somewhathigher than the level of the actuating lever 14 in the position d. Theabove described Fig. 7 explains this embodiment of the post; the levelof the actuating lever I4 in the position a is substantially equal tothe level of the actuating lever in the position 41, and, as accordingto Fig. 7 the post 88 must form a stop to arrest the actuating leverwhen the latter is advanced in the direction of the arrow Z, at least aportion of the post must be higher than the level of the actuating leverin position a or d. Now, during the return movement of .the actuatinglever I4 from the position d into the position e as shown in Fig. 9, theactuating lever contacts the inclined surface H2 at the lower pointthereof. The inclined surface I I2 tilts the actuating lever to acertain degree against the action of the spring 82 into the posidition dand guides the actuating lever over the post 88. After the passage overthe post 88 the actuating lever is returned into the level of theposition d, i. e. the level of the position e is substantially equal tothe level of the position d. As pointed out above, the abutment I82 ofthe blade carrier 88 also has an inclined surface I88, and the inclinedsurfaces I84 and I I2 of the abutment I82 and the post 88 are inalignment with each other when the abutment I82 rests against the post88 as shown in Fig. 9. If, for any reason the actuating lever 18 shoulddrop to a certain degree from the level of its position d during itsreturn movement, the inclined surface I88 leads the actuating lever 14onto the inclined surface H2, so that the actuating lever is not caughtby the lower edge of the inclined surface I I2. when the elements of theshutter mechanism are returned into theposition shown-in Fig. 1, theshutter is ready for the next operation.

- Instantaneous exposure The setting mechanism is set for"instantaneous" exposure. For this purpose the ring 88 is rotated aboutthe shoulder 48 into a position, in which the stop 88 contacts the lefthand end H8 of the slot 88 as shown in Figs. 5 and 6. Then, the trigger82 is rotated in clockwise direction about its pivot 82. During thefirst part of the "instantaneous exposure, the movements of the elementsof the shutter mechanism are the same as during the first part of theabove described bulb-exposure, i. e. the actuating lever 18 is arrestedby the post 88 for the tensioning 01' its spring 82 as shown in Figs. 2and 7 and the blade carrier 88 is actuated by the actuating lever assoon as the free end thereof has been moved past the edge II8 of thepost. Now, in contrast to the above described bulb-exposure, the stop 88contacting the left hand edge Ill of the slot 88 does not limit themovement of the blade carrier 88, so that the latter may be swungthrough a larger angle into the position shown in Fig. 5. However,before the blade carrier is swung into this extreme position shown inFig. 5, the trigger 82 has already reached its end active position withits abutment 88 contacting the wall of the center portion 82. Now, theactuating lever 18 is further rotated about its pivot I8 by the spring82, whereby the rotation of the unobstructed blade carrier 98 iscontinued. Owing to the eccentric arrangement of the pivot 18, the freeend of the actuating lever I8 slides along the abutment I82 of the bladecarrier during said rotation of the actuating lever. As soon as theactuating lever is moved past the edge of the abutment I82, theactuating lever and the blade carrier are disengaged from each other, sothat the spring 82 immediately returns the blade carrier from itsextreme position shown in Fig. 5 into its normal position shown in Fig,6, in which the blade carrier holds the shutter blades in closingposition. At the same time the actuating lever 18," is moved from itsposition I (Fig. 10) into the position a by the action of its spring 82.In the position g the end of the actuating lever 1| rests against thewall of the center portion 82 as shown in Figs. 6 and 10. Now, when theuser of the shutter releases the trigger 82, the cam I8 of the triggerlifts the actuating lever 18 from the position g into the position It asshown in Fig. 11, whereupon the actuating lever is moved above the post88 into the starting position e as described above in connectionwithFig. 9. At the end of the return movement of the trigger, the elementsof the actuating mechanism are again in the position shown in Fig. l,with the exception that the stop 58 of the setting mechanism contactsthe left hand edge Ill of the slot 56. Now, the shutter is ready for thenext operation.

As best shown in Figs. 1620, the two shutter blades used in the shutterare of such a specific form, that. in an intermediate position of theshutter blades, the portion of the light admitting aperture 86 liberatedby the shutter blades is of substantially triangular shape, so that theoptical effect caused by the two-blade shutter is phasized, however,that, although the above described shutter mechanism is of specialadvantage for the use of my specific shutter blades, I do not wish to belimited to the use of the specific shutter blades shown in the drawingsin connection with my new shutter mechanism; any other form of shutterblades could be used in a shutter equipped with my shutter mechanism. Onthe other hand, it will be understood, that shutter blades of thespecific form shown in the drawings and described hereinafter may beused in shutters equipped with different types of shutter mechanisms. Inother words, my invention is not restricted to the combination of thespecific shutter mechanism with the. specific shutter blades but is alsoconcerned with the mechanism per se as well as with the shutter bladesper se.

Fig. 16 illustrates only one shutter blade in an enlarged scale, i. e.the shutter blade 34, but it will be easily understood that the othershutter blade 95 is of identical form. Fig. 16 shows four differentrelative positions between the shutter blade and the light admittingaperture 30. For the sake of better illustration, the shutter blade isshown as remaining in the same position and the aperture is shown asbeing rotated about the pivot 44 of the shutter'blade although in thereal shutter the aperture is stationary and the shutter blade is rotatedabout its pivot. The position 38 of the aperture indicates the closingposition of the shutter blades as shown in Fig. 17, the position 36' ofthe aperture indicates a first intermediate opening position of theshutter blades as shown in Fig. 18, the position 36" of the apertureindicates a second intermediate opening position of the shutter bladesas shown in Fig. 19, and the position 36" of the aperture indicates thefully opened position of the shutter blades as shown in Fig. 20.

The light controlling slot I20 of the shutter blade has an outer portionI22 and an inner portion I24. The edges I26 and I20 of the outer portionI 22 of the slot are circles about the center of the pivot 44. Theradial distance between the edges I26 and I20 is equal to the diameterof the aperture 36, and the edges I20 and I28 contact the circumferenceof the aperture at the. points F and G respectively when the aperture isin the position 36" for fully opened shutter blades. The inner portionI24 oi the light controlling slot I20 has convergent edges I30 and I32meeting each other at the theoretical apex L of the inner portion. Inpractice, however, the corner I34 of the inner portion I24 is slightlyrounded as shown in solid lines in Fig. 16. The circular edges I26 andI28 of the outer portion I22 merge into the convergent edges I30 and I32of the inner portion I24 at the points H and K respectively. Theconvergent edges I30 and I32 are substantially straight; if desired,however, they may be curved as indicated by the dash and dotted linesI35 in Fig. 17.

The shape of the inner portion I24 of the slot I20 determines thevarying shapes of the portions of the aperture liberated by the twoshutter blades during their opening movement. One object of my inventionis to provide a two-blade shutter in which at the beginning of theopening movement of the shutter blades the portion of the lightadinitting aperture :5 liberated by the shutter blades has the form of adrop I30 (see Fig. 18), whereupon during the continuation of the openingmovement of the shutter blades the shape of the gradually increasingliberated portion of the light admitting aperture 30 is changed to atriangle I40 or the like with the center M of the aperture 38substantially in'the middle of said triangle (see Fig. 19), until at theend of the opening movement of the shutter blades the circular aperture30 is entirely'liberated as shown in Fig. 20. A two-blade shutter withthese features provides substantially the same optical effeet as ahitherto usual more complicated threeblade shutter. The above describedfeatures of the two-blade shutter require a certain relation-' shipbetween the position of the convergent edges I30, I32 and the pivot 44.The angle a between the convergent edges I30 and I32 is determined bythe position of the points H, K and L (see Figs. 16). I have found thatthe best results are obtained when the points H and K are as near aspossible to the circumference of the light admitting aperture in theposition 30" and when the apex L is as near as possible to the center Mof the aperture in the position 30. In order to secure an absoluteclosing of the aperture by a slight overlapping of the blades in theirclosing position, I prefer to arrange the apex L at a small horizontaldistance m from a vertical line drawn through the center M and at asmall radial distance n from said center M. In the embodiment of theshutter blade shown in Fig. 16, the points H and K are outside thecircumference of the aperture in the position 38" for the followingreasons. As has been pointed out above, the angle of rotation of theblade carrier 90 is slightly smaller for the bulb"-exposure than for theinstantaneous"-exposure. Therefore the extreme end position of theshutter blades in bu1b"- exposure does not coincide with the extreme endposition of the shutter blades in instantaneousexposure. The lightadmitting aperture is fully opened during the bulb"-exposure, when theconvergent edges I30, I 32 form tangents to the circumference in theextreme bulb-end-position of the shutter blade. Under thesecircumstances, however, the convergent edges I30, I32 cannot formtangents to the circumference of the aperture when the shutter blade isin its extreme "instantaneous"-end-position as shown in Fig. 16.

Therefore, the points H and K are outside the circumference of theaperture in Fig. 16. Of course, if the shutter blades are used in ashutter equipped with a different type of a shutter mechanism, in whichthe shutter blades reach the same end position for all types ofexposures, the points H and K may be positioned on the circumference ofthe aperture in the position 36", so that the edges I30 and I32 formtangents to the circumference of the aperture in this position.

If desired, the apex L may be arranged at any other point within theboundary of the aperture 38 when the shutter blades are in closingposition. This alteration, however, varies the form and the relativeposition of the triangular or substantially triangular area I40liberated by the shutter blades during the opening movement and requiresdifferent angles of rotation of the blade carrier 90.

It should be understood that the embodiments shown in the drawings andabove described are by way of illustration only, and that I contemplateas within the scope of my invention all such forms and embodiments asmay come within the scope of the claims.

What I claim is:

l. A photographic shutter comprising: shutter blades, a pivoted bladedriving means for operating said shutter blades, a first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for returning sameinto its normal inactive position, a spring pressed actuator, saidactuator being movably connected with said trigger and being disengagedfrom said blade driving means when the trigger is in its normal inactiveposition, said actuator being adapted to be brought into engagement withsaid blade driving means, stationary means in the path of said actuatorfor causing a relative movement between the trigger and the actuator totension the spring of said actuator during the movement of the triggerinto active position, and means for releasing the spring pressedactuator for an engagement with the blade driving means so as to actuatesame.

2. A. photographic shutter comprising: shutter blades, 9. pivoted bladedriving means for operating said shutter blades, a first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for re-' turning sameinto its normal inactive position, a spring pressed actuating lever,said actuating lever being hinged to said trigger at an eccentric pointthereof and being disengaged from said blade driving means when thetrigger is in its normal inactive position, said actuating lever beingadapted to be brought into engagement with said blade driving means,means for providing joint movements of said trigger and actuating lever,stationary means in the path of said actuating lever for causing arelative movement between the trigger and the actuating lever to tensionthe spring of said actuating lever during the movement of the triggerinto active position, and means for releasing the spring pressedactuating lever for an engagement with the blade driving means so as toactuate same.

3. A photographic shutter comprising: two interlocked shutter blades, 9,pivoted blade driving means for operating said shutter blades, a firstspring connected to said blade driving means for returning same into itsnormal position to hold the shutter blades in closing position, apivoted trigger, a second spring connected to said trigger for returningsame into its normal inactive position, one of said shutter blades beingswingably mounted on the pivot of the blade driving means, the othershutter blade being swingably mounted on the pivot of the trigger, aspring pressed actuating lever, said actuating lever being hinged tosaid trigger at an eccentric point thereof and being adapted to actuatesaid blade driving means, means for providing joint movements of saidtrigger and actuating lever, means for causing a relative movementbetween the trigger and'the actuating lever to tension the spring ofsaid actuating lever during the movement of the trigger into activeposition, and means for releasing the spring pressed actuating lever toactuate the blade driving means,

4. A photographic shutter comprising: shutter blades, a pivoted bladedriving means for operating said shutter blades, 9, first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for returningsameinto its normal inactive position, a spring pressed actuating lever,said actuating lever being hinged to said trigger at an eccentric leverfor moving away the actuating lever from the abutment of the trigger totension the spring of the actuating lever during the movement of thetrigger into active position, said eccentric arrangement of theactuating lever causing a disengagement of the actuating lever from thepost at a predetermined moment during the movement of the trigger torelease the spring pressed actuating lever for actuating the bladedriving means, and means for lifting said actuating lever to pass oversaid post during the return movement of the trigger,

5. A photographic shutter comprising: shutter blades. a pivoted bladedriving means for operating said shutter blades, a first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for returning sameinto its normal inactive position, a spring pressed actuating lever,said actuating lever being hinged to said trigger at an eccentric pointthereof and being adapted to actuate said blade driving means, a cam onsaid trigger for cooperation with said actuating lever to lift and lowersame, an abutment on said trigger, the spring of said actuating .leverpressing same against said cam and normally urging same against saidabutment for providing joint movements of said trigger and saidactuating lever,

a post in the path of said actuating lever for moving away the actuatinglever from the abutment of the trigger to tension the spring of theactuating lever and to cause a lowering of the actuating lever by saidcam during the movement of the trigger into active position, saideccentric arrangement of the actuating lever causing a disengagement ofthe actuating lever from the post at a predetermined moment during themovement of the trigger to release the spring pressed actuating lever toactuate the blade driving means, and said cam lifting said actuatinglever during the return movement of the trigger.

6. A photographic shutter comprising: shutter blades, a pivoted drivingmeans for operating said shutter blades, a first spring connected tosaid blade driving means for returning same into its normal position tohold the shutter blades in closing position, a pivoted trigger, a secondspring connected to said trigger for returning same into its normalinactive position, a spring pressed actuator, said'actuator beingmovably connected with said trigger and being disengaged from said bladedriving means when the trigger is in its normal inactive position, saidactuator being adapted to be brought into engagement with said bladedriving means, stationary means in the path of said actuator for causinga relative movement between the trigger and the actuator to tension thespring of said actuator during the movement of the trigger into activeposition, means for releasing the spring pressed actuator to engage andactuate the blade driving means, an adjustable setting mechanism forbulb and instantaneous exposures, stopping means associated with saidadjustable setting mechanism, said stopping means being in a positionfor arresting the shutter mechanism prior to a disengagement of theactuator from the blade driving means when the setting mechanism is setfor "bulb exposure, and means for disengaging the actuator from theblade driving means during the return movement of the trigger. a

7. A photographic shutter as claimed in claim 6, said shutter havingmeans for disengaging the actuator from the blade driving means at theend of the movement of the trigger into active position, and saidstopping means being in a position for permitting the disengagement ofthe actuator from the blade driving means at the end of the movement ofthe trigger into active position when the setting mechanism is set forinstantaneous" exposure.

8. A photographic shutter comprising: shutter blades, a pivoted bladedriving means for operating said shutter blades, a first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for returning sameinto its normal inactive position, a spring pressed actuator, saidactuator being movably connected with said trigger and being disengagedfrom said blade driving means when the trigger is in its normal inactiveposition, said actuator being adapted to be brought into engagement withsaid blade driving means, stationary means in the path of said actuatorfor causing a relative movement between the trigger and the actuator totension the spring of said actuator during the movement of the triggerinto active position, means for releasing the spring pressed actuator toengage and actuate the blade driving means, an adjustable settingmechanism for bulb and instantaneous exposures, a stop arranged on saidadjustable setting mechanism, said stop being in the path of said bladedriving means when the setting mechanism is set for "bulb" exposure forarresting the shutter mechanism prior to the disengagement of theactuator from the blade driving means. and mean for disengaging theactuator from the blade driving means during the return movement of thetrigger.

9. A photographic shutter as claimed in claim 8, said stop being outsidethe path of said blade driving means when the setting mechanism is setfor instantaneous" exposure, and means for disengaging the actuator fromthe blade driving means at the end of the movement of the trigger intoactive position.

10. A photographic shutter comprising: shutter blades, a pivoted bladedriving means for operating said shutter blades, a first springconnected to said blade driving means for returning same into its normalposition to hold the shutter blades in closing position, a pivotedtrigger, a second spring connected to said trigger for returning sameinto its normal inactive position,

a spring pressed actuating lever, said actuating lever being hinged tosaid trigger at an eccentric point thereof and being adapted to actuatesaid blade driving means, a camon said trigger. said cam cooperatingwith said actuating lever to lift and lower same, an abutment on saidtrigger, the spring of said actuating lever pressing same against saidcam and normally urging same against said abutment for providing jointmovements of said trigger and said actuating lever, a post in the pathof said actuating lever for moving away the actuating lever from theabutment of the trigger to tension the spring of the actuating leverduring the movement of the trigger into active position, said eccentricarrangement of the actuating lever causing a disengagement of theactuating lever from the post at a predetermined moment during themovement of the trigger to return the spring pressed actuating lever forengaging and actuating the blade driving means, an adjustable settingmechanism for bulb" and instantaneous" exposures, and stopping meansassociated with said adjustable setting mechanism, said stopping meansbeing in a position for arresting the shutter mechanism prior to thedisengagement of theactuating lever from the blade driving means whenthe setting mechanism is set for bulb exposure, and said cam liftingsaid actuating lever and disengaging same from the blade driving meansduring the return movement of the trigger.

11. A photographic shutter as claimed in claim 10, said eccentricarrangement of the actuating lever causing a disengagement of theactuating lever from the blade driving means at the end of the movementof the trigger into active position, said stopping means being in aposition for permitting the disengagement of the actuating lever fromthe blade driving means at the end of the movement of the trigger intoactive position when the setting mechanism is set for "instantaneousexposure, and means for lifting said actuating lever to pass over saidpost during the return movement of the trigger,

12. A photographic shutter as claimed in claim 10, said eccentricarrangement of the actuating lever causing a disengagement of theactuating lever from the blade driving means at the end of the movementof the trigger into active position, said stopping means being in aposition for permitting the disengagement of the actuating lever fromthe blade driving means at the end of the movement of the trigger intoactive position when the setting mechanism is set for instantaneous"exposure, the free end of said post having an inclined surface to guidesaid actuating lever over said post during the return movement of thetrigger, and said cam lifting said actuating lever up to the lower levelof said inclined surface,

ERIC STRASSENBURG.

